Modified exosomes for targeted delivery of doxorubicin and carvedilol to mitochondria in breast cancer cells

Carvedilol (CAR), a well-established β-blocker and a promising pharmacological agent for mitigating doxorubicin (DOX)-induced cardiotoxicity, has also demonstrated anticancer effects against breast cancer cells. Given the seemingly contradictory effects of CAR and DOX treatment on cardiomyocytes and cancer cells, particularly regarding mitochondrial function, this study investigates the synergistic potential of DOX and CAR through various delivery systems, including free form, exosomal formulations, and mitochondria-targeted delivery systems. The Chou-Talalay analysis demonstrated that combining DOX with CAR at a 1:1 ratio reduced DOX's IC50 in MCF-7 (from 0.274 µM to 0.191 µM) and MDA-MB-231 (from 0.138 µM to 0.086 µM) cells. Drug loading in exosomal formulations was achieved with approximately 24% efficiency, maintaining the optimum ratio. While CAR exhibited minimal cytotoxicity at concentrations below 2 µM, its combination with DOX enhanced anticancer effects. Mitochondrial-targeted delivery (TPP-Exo-DOX-CAR) showed reduced cytotoxicity compared to TPP-Exo-DOX formulation. ROS production analysis and mitochondrial membrane potential assessments revealed that CAR's protective effects become dominant in mitochondria-targeted delivery in vitro. Migration studies demonstrated significant inhibition of cell motility in CAR containing formulations. These findings suggest that while the DOX and CAR combination shows promise in cancer treatment, the delivery system significantly impacts their therapeutic efficacy, particularly in mitochondrial-targeted applications.